Individual DFD Assignment

Library Information System

The University library system records the books owned by the library as well as any new books purchased and put into circulation. Before someone can borrow a book, he or she must show a valid ID card that is checked – to ensure that it is still valid – against the student files maintained by the registrar’s office (for student borrowers), the faculty/staff files maintained by the personnel office (for faculty/staff borrowers), or the library’s own guest file (for individuals issued a guest card by the library). The system must also check to ensure the borrower does not have any overdue books or unpaid fines before he or she can borrow another book. If no fines or overdue books are found, the book is checked out. The system should record who has borrowed what book and when it is due back. The borrower is also told the due date. Books can only be checked out for two weeks. When a book is overdue, the information about the book and the person who checked it out is added to an overdue file. Every Monday, the library prints and mails postcards to those people with overdue books. If a book is overdue by more than one month, a fine will be imposed and a librarian will telephone the borrower to remind him or her to return the book.

Library Information System

• Task at Hand– You are to create a Context diagram as well as a Level 1

decomposition of the Library Information System• The processes described on the previous slide must be represented

in the Level 1 decomposition

• All relevant data stores must be represented in the Level 1 decomposition

– A USD diagram is to be created that depicts the existing system ichnographically

– An entity relationship diagram, using correct cardinality notation, is to be included to represent the relationship between the different data stores

Library Information System

• Data Flow Diagrams– Context diagram should highlight “boundaries”– 1st level decomposition should cover general functions

• Entity Relationship Diagram– Basic relationships between “data stores”

• User System Diagram– Reflect Context & level 1 decomposition functions

• Diagrams can be created using VISIO (via citrix), using MS word, or any other drawing tool– Proper notation for “cardinality” should be user in the ERD– Proper symbols must be used for the DFD

• DUE March 1st by 5:00 pm